The remains of the primary

With Mitt Romney’s sweep of Maryland, Wisconsin, and the District of Columbia on Tuesday night, the situation looks grim for his rivals.

Romney has passed the halfway point of delegates needed to secure the nomination, with 652 delegates on his scorecard, compared to only 269 for Rick Santorum, 140 for Newt Gingrich, and 67 for Ron Paul, with 1,144 needed to win. However, nothing in this primary race is simple, including those delegate totals, because there are “unbound” delegates with the freedom to vote however they choose.

Nothing about the remaining primary landscape is simple, either. The states have different rules about how delegates are assigned. Only three of those remaining states – Delaware on April 24, New Jersey on June 5, and Utah on June 26 – follow the simplest model of “winner take all.” These states account for only 107 delegates between them.

The rest of the states, including the big jackpots of Texas and California, assign their delegates either by district, or proportionally according to popular vote totals, with a few of those unbound super-delegates thrown in for good measure. And then you’ve got the non-binding caucuses. That puts 894 delegates up for grabs, to be divided proportionally, according to a stack of conflicting rules that would give Stephen Hawking a migraine.

Making “winner take all” primaries rare inevitably leads to this kind of long delegate slog. A come-from-behind candidate can’t just hope to win a couple of big states and vault into the lead. Strong victories might only translate into a net gain of a few delegates. Polls that show someone with a double-digit lead in a certain state might not reflect a proportional increase in electoral position.

Adding to the complexity is the difficulty of predicting what might happen if a candidate dropped out of the race. These speculations are most often floated around Newt Gingrich, since Ron Paul isn’t going anywhere. A look at the “second choice” revealed in polls of Gingrich voters suggests that they would not break all that heavily for Santorum, bolstering Gingrich’s contention that his continued presence in the race hurts Romney. However, it’s tough to model what those voters might do if Gingrich exited the race and strongly endorsed Santorum. At the moment, the point is moot, because Gingrich maintains he’s going all the way to the Republican convention.

This leaves us with two separate questions: can anyone but Romney get to 1,144 delegates, and can Romney be prevented from reaching that threshold, bringing us that fabled “brokered convention?” The answer to the former question is a fairly firm “no,” particularly with the results of Tuesday night’s Romney victories factored in. In the simplest analysis, if Santorum won all three of the remaining winner-take-all states, he’d get to 376 delegates. He would then need to win 768 of the remaining 894 proportionally awarded delegates, which just isn’t going to happen. Santorum’s task is eased somewhat by the super-delegates, but he’d have to win over an equally lopsided percentage of them. Barring some incredible development that all but knocks Mitt Romney out of the race, that’s as close to “impossible” as political questions usually get.

The more pertinent, and difficult, question is whether Santorum, Gingrich, and Paul can manage to keep Romney from getting to 1,144 delegates. The immediate political terrain is generally favorable to Romney. After a three-week break, the contest resumes on April 24 with Connecticut, Delaware, New York, Rhode Island… and Pennsylvania, Santorum’s home state, which has become a real wild card in this race.

A gut-check poll from Franklin & Marshall College in late March had Santorum with a margin-of-error 2-point lead, but Qunnipiac produced a poll the following week that had Santorum ahead by a more comfortable, if not commanding, 6 points. A big Pennsylvania win would be crucial for Santorum, while a narrow victory leaves him floating on calm seas with dead sails, and a loss to Romney would blow him out of the water. Modeling anything beyond April 24 is therefore incredibly difficult, until we know how Pennsylvania shakes out.

The New Yorkerpublished a set of predictions from Ryan Lizza, Joshua Putnam, and Andrew Prokop on Tuesday, before Romney’s latest round of primary wins. Using models based on partisan voting patterns and the population of evangelical voters in each state, their best guess was that Romney would end up with 1,122 delegates… which is just a bit shy of the total he needs. That gap would not be difficult to close by attracting a couple dozen super-delegates, so the authors concluded that the race is “pretty much” over – and that was written before Romney won in Wisconsin and Maryland.

Besides the potential shock waves coming from Pennsylvania, the other factor that cannot easily be modeled is sense of completion falling over voters as Romney’s total increases, and the number of possible – let alone plausible – scenarios for denying him the nomination diminishes. Some people want to see that brokered convention, but a lot of others don’t.

Throughout this long primary season, I have wondered why the voters of Texas and California should have so many of their decisions made by Iowa and New Hampshire, but that’s how it works. The dearth of winner-take-all states reduces the odds of a dramatic reversal, while the calendar creates an inescapable momentum. Some very good states are coming up for Mitt Romney – he’s up 15 points in New York according to the latest polls, and 95 delegates can be found there. Those results will surely weigh upon the decisions of voters in the final May and June states. The 2012 GOP primary will have a long curtain call, but it’s hard to argue that the curtains are not closing.